Mass outflow rate from accretion discs around compact objects

Abstract

We compute mass outflow rates from accretion discs around compact objects, such as neutron stars and black holes. These computations are done using combinations of exact transonic inflow and outflow solutions which may or may not form standing shock waves. Assuming that the bulk of the outflow is from the effective boundary layers of these objects, we find that the ratio of the outflow and inflow rates varies anywhere from a few per cent to even close to a 100% (i.e. close to the disc evacuation case) depending on the initial parameters of the disc, the degree of compression of matter near the centrifugal barrier, and the polytropic index of the flow. Our result, in general, matches the outflow rates obtained through a fully time-dependent numerical simulation. In some region of the parameter space when the standing shock does not form, our results indicate that the disc may be evacuated and may produce quiescence states.